Electric-arc lamp



Patented Feb. 15, 1927.

UNETED STATES PATENT OFFICE.

JOHN: ALLEN HEANY, OF NEW HAVEN, CONNECTICUT, ASSIGNOR TO HEANY LABORA: TORIES, INC, OFIIEW HAVEN, CONNECTICUT, A CORPORATION OF CONNECTICUT.

ELECTRIC-ARC LAMP.

Application filed June 11, 1917, Serial No. 174,104. Renewed December 6, 1926.

The invention relates to electric arc lamps operating on very low wattages and at the ordinary commercial voltages, and maintaining high efiiciencies even in the smaller sizes ranging as low as ten or fifteen candle power. To this end, the invention comprises a lamp, involving a container or envelope, preferably adapted for connection in the ordinary incandescent lamp socket and containing an inert gas, preferably under diminished pressure, and two electrodes, between which an arc is established and maintained, connected to suitable lead wires, at least one 4 of which electrodes comprising a rod or tube formed of material WhlCll 1s a second class conductor, which is normally non-conducting when cold, but-becomes conductive when heated to a high degree, one or both of said electrodes being surrounded by a coil of wire formed of highly refractory metal, such as tungsten, which coil or coils is or are in series with said electrodes, after the arc has been established and are normally in series with a shunt or by-pass about the electrodes,

' which shunt is provided with separable contacts, which contacts are adapted to be separated by suitable means, preferably a thermostat, which also serves to move the electrodes'apart to proper arcing distance, said coil or coils serving as ballast resistance, luminants per se, heaters to raise the electrodes to a temperature suflicient to render them conductive and to ionize the gaseous medium about the electrodes and also to heat the thermostat to render the same operative.

In the accompanying drawing,

Fig, 1 illustrates a lamp involving the invention.

Fig. 2 shows a modifiedform of shunt orv by-pass involving a ballast resistance.

Referring to the drawings, 1 indicates the globe or bulb of the lamp, which ispreferably in the form usually employed in incandescent filament lamps, adapted for the usual socket connection, which bulbis exhausted of air and supplied with an inert gas, such as nitrogen, argon, or the like, preferably under diminished pressure. The bulb is provided with the usual form of glass neck 2 in which the lead wires connected to the terminals of the lamp are imbedded and to the lower end of which neck is se cured a glass stem 2.

To the lower end of stem 2 is attached a supporting wire 3 which carries at its lower end by means of a clamp 3* a rod-like element 6 made of second class conductive material, such as an admixture of oxides of zir conium, thorium and yttrium. A second electrode 7, which may be made of the same material as electrode 6, is mounted on the lower end of a thermostat 10 through the medium of a clamp 10 carried by the wire 10 fused to the thermotat, the upper end of which is supported from 'the glass stem 2.

A lead 4 connected to one terminal of the lamp and anchored in the stem 2 is con nected at its lower end to coil 5 of highly refractory metal wire, such as tungsten, which surrounds the electrode 6 and is connected to the outer end of said electrode. A similar lead 9 is connected to a similar coil 8 surrounding electrode 7 and connected to the outer end thereof.

To the outer ends of the coils 5 and .8 are connected leads 11 and 12, which are provided with contacts 13 and 14, which are normally in engagement and constitute with said leads 11 and 12, a shunt or by-pass around the arc gap between the ends of electrodes 6 and 7, which bypass is in series with the coils 5 and 8.

When current is supplied to the lamp, it enters by way of lead 4, passes through coil 5, thence through by-pass formed by lead 11, contacts 13, 14, lead 12, to and through coil 8, and thence by way of lead 9, back to the other terminal of the lamp. The immediate effect of the passage of the current is 'to raise the coils 5 and 8 to incandescence, and the high temperature developed heats the second class conductor bodies 6 and 7 to a degree 'sufiicient to render them conductive, so that the current will pass from coil 5 through the electrode 6, across the arc gap to electrode 7, thence through coil 8, and

lead 9 to the other terminal of the lamp. At

the same time, the generated heat causes thermostat 10 to operate and withdraw electrode 7 away from electrode 6 to proper arcing distance 'and simultaneously break the brilliant light, generated by the arc, whit h is augmented by the incandenscence of the coils 5 and 8 and of the refractory oxide constituting the electrodes 6 and 7. The coils 5 and 8, therefore, serve as ballast for the lamp, as well as heating elements for the electrodes, and the thermostat and as luminants per se; They also effect the preliminary ionization of the gas between the electrodes, whereby the arc is initially established.

In the modification shown in' Fig. 2, a ballast resistance is interposed in the shunt or by-pass, substantially equal to the resistance of the are. This is found to be of advantage under certain circumstances, in that when the electrode is heated sufiiciently to become conductive.

2. An arc lamp comprising a container, electrodes therein, at least one of which is formed of a second class conductor, a highly refractory wire in series with said conductor while current flows through it and in heating relation therewith, circuit connections for the respective electrodes including said wire, a normally closed shunt around said electrodes, and a thermostat adapted to move one trodes; and means to break the shunt when the electrodes are heated sufliciently to become conductive.

4. An arc lamp comprising a container, electrodes therein at least one of which is formed of a second class conductor, a resistance coil in series with said conductor while current flows through it and in heating relation therewith, circuit connections for the respective electrodes including said coil, a normall closed shunt around said electrodes, an means adapted to break the shunt when the electrode is heated sufliciently to become conductive.

5. An are lamp comprising a. container, electrodes therein one of which is formed of material constituting a second class con ductor, a heating coil for said conductor in series with it while the current flows through the conductor, a shunt around said electrodes and means for rendering said shunt electrically ineffective when current is flowing through the electrodes.

In testimony whereof I aflix my-signature.

JOHN ALLEN HEANY. 

